Yes, the Jackson manual parser design is quite different from other libraries. In particular, you will notice that JsonNode has most of the functions that you would typically associate with array nodes from other APIs. As such, you do not need to cast to an ArrayNode to use. Here's an example:

JSON:

{
    "objects" : ["One", "Two", "Three"]
}

Code:

final String json = "{\"objects\" : [\"One\", \"Two\", \"Three\"]}";

final JsonNode arrNode = new ObjectMapper().readTree(json).get("objects");
if (arrNode.isArray()) {
    for (final JsonNode objNode : arrNode) {
        System.out.println(objNode);
    }
}

Output:

"One"
"Two"
"Three"

Note the use of isArray to verify that the node is actually an array before iterating. The check is not necessary if you are absolutely confident in your data structure, but it's available should you need it (and this is no different from most other JSON libraries).

If you want to explicitly traverse through the json and find the value of a , you can do it like this for the json that you specified.

String aValue = jsonNode.get("text").get(0).get("a").asText();

Finding the value of b would be

String bValue = jsonNode.get("text").get(1).get("b").asText();

You can also traverse through the elements within the text array and get the values of a and b as

for (JsonNode node : jsonNode.get("text")) {
    System.out.println(node.fields().next().getValue().asText());
}

And that would print the below on the console

1
2

As you said its an Array. Cast the node to an ArrayNode. Select the first element [0] and call the getter. Should be it. Or check out this: https://stackoverflow.com/a/16793133/15565539

Moving my comment to an answer, as it got upvoted a lot.

This should do what the OP needed:

new ObjectMapper().convertValue(jsonNode, ArrayList.class)